1. Field of the Invention
The present invention relates to a head restraint with a basic structure which serves to adjust the head restraint and to receive a person's head.
2. Description of the Background Art
“Function-integrated, bionic car seats” are known from the prior art. The particular feature of these seats lies in the design of the backrest, which utilizes a fin ray principle. The use of this principle and the basic structure, the so-called fin ray structure, have already been described in EP 1 040 999 A2 for the construction of structural elements, such as backrests and seat areas.
A fin ray principle can be observed in fish. It is based on the special structure of the fin rays of fish. When a point is pressed, the principle causes the fin ray to move opposite to this pressure direction. The fin ray reacts to the pressure with counterpressure. This becomes possible because of the special structure of the fin ray with two flexible struts, which converge at a tip and there grow together solidly. Cross struts, which keep the flanks at a distance and allow elastic movements, are located between the two elastic flanks. If the tail ray is held firmly at the base and the middle of the fin blade is pressed with a finger, the fin tip contrary to expectations moves opposite to the pressing direction of the finger.
This operating principle was realized technically in a backrest structure of a car seat in the following manner: Two flexible flanks made of thermoplastic fiberglass composite (a so-called organic sheet) form the front and back of the backrest. These are attached at the bottom to the backrest base, run together tapering upwards, where their ends are connected. Struts attached in an articulated manner to the flanks connect the front and back sides and keep these at a distance. Such a backrest also provides support in the lumbar area, yields in the shoulder region mostly toward the back, and thereby simultaneously reduces the distance of a head cushion of a head restraint to the head of a seat occupant. In large displacements, as may also occur, for example, in a rear-end collision, whiplash injury can be effectively countered with the aid of such a backrest structure. Thus, an anti-whiplash effect in the head area can be achieved with such a backrest structure.
A vehicle seat that utilizes the fin ray principle is described in the publication DE 10 2005 054 125 B3. The backrest frame of the vehicle seat comprises a construction built on the fin ray principle in a frame-like fashion; the construction comprises a rigid rear wall, a flexibly formed plate-like front wall, and cross struts arranged between them. The cross struts extend in their longitudinal direction along the vehicle seat width direction. The front wall and rear wall, in contrast, have a longitudinal extension in the vehicle height direction. The publication provides a backrest of a vehicle seat, which can be deformed in a simple way by using the fin ray principle both in the lumbar and in the shoulder region with mutual interdependence.
Thus far, in the automotive sector it was only envisaged to develop a backrest whose upper part functions as a head restraint in a crash. The upper part of the backrest moves forward in the crash and thus prevents the head from falling backwards and the cervical spine from hyperextending. As mentioned above in the event of a crash, the so-called anti-whiplash effect is achieved thereby for the head of a vehicle occupant.